4K71

Crystal structure of a high affinity Human Serum Albumin variant bound to the Neonatal Fc Receptor

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.212 
  • R-Value Observed: 0.214 

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This is version 1.1 of the entry. See complete history. 


Literature

Crystal structure of an HSA/FcRn complex reveals recycling by competitive mimicry of HSA ligands at a pH-dependent hydrophobic interface.

Schmidt, M.M., Townson, S.A., Andreucci, A.J., King, B.M., Schirmer, E.B., Murillo, A.J., Dombrowski, C., Tisdale, A.W., Lowden, P.A., Masci, A.L., Kovalchin, J.T., Erbe, D.V., Wittrup, K.D., Furfine, E.S., Barnes, T.M.

(2013) Structure 21: 1966-1978

  • DOI: 10.1016/j.str.2013.08.022
  • Primary Citation of Related Structures:  
    4K71

  • PubMed Abstract: 

    • The long circulating half-life of serum albumin, the most abundant protein in mammalian plasma, derives from pH-dependent endosomal salvage from degradation, mediated by the neonatal Fc receptor (FcRn). Using yeast display, we identified human serum ...

    The long circulating half-life of serum albumin, the most abundant protein in mammalian plasma, derives from pH-dependent endosomal salvage from degradation, mediated by the neonatal Fc receptor (FcRn). Using yeast display, we identified human serum albumin (HSA) variants with increased affinity for human FcRn at endosomal pH, enabling us to solve the crystal structure of a variant HSA/FcRn complex. We find an extensive, primarily hydrophobic interface stabilized by hydrogen-bonding networks involving protonated histidines internal to each protein. The interface features two key FcRn tryptophan side chains inserting into deep hydrophobic pockets on HSA that overlap albumin ligand binding sites. We find that fatty acids (FAs) compete with FcRn, revealing a clash between ligand binding and recycling, and that our high-affinity HSA variants have significantly increased circulating half-lives in mice and monkeys. These observations open the way for the creation of biotherapeutics with significantly improved pharmacokinetics.

    Organizational Affiliation: 

    Eleven Biotherapeutics, Inc., Cambridge, MA 02142, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Serum albuminA, D585Homo sapiensMutation(s): 4 
Gene Names: ALB, GIG20, GIG42, PRO0903, PRO1708, PRO2044, PRO2619, PRO2675, UNQ696/PRO1341
Find proteins for P02768 (Homo sapiens)
Explore P02768 
Go to UniProtKB:  P02768
NIH Common Fund Data Resources
PHAROS  P02768
GTEx  ENSG00000163631
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
IgG receptor FcRn large subunit p51B, E274Homo sapiensMutation(s): 0 
Gene Names: FCGRT, FCRN
Find proteins for P55899 (Homo sapiens)
Explore P55899 
Go to UniProtKB:  P55899
NIH Common Fund Data Resources
PHAROS  P55899
GTEx  ENSG00000104870
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  • Reference Sequence
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
Beta-2-microglobulinC, F99Homo sapiensMutation(s): 0 
Gene Names: B2M, CDABP0092, HDCMA22P
Find proteins for P61769 (Homo sapiens)
Explore P61769 
Go to UniProtKB:  P61769
NIH Common Fund Data Resources
PHAROS  P61769
GTEx  ENSG00000166710
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.212 
  • R-Value Observed: 0.214 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 127.893α = 90
b = 203.536β = 90
c = 100.561γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
REFMACrefinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-10-23
    Type: Initial release
  • Version 1.1: 2014-02-05
    Changes: Database references